The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

Greens want federal protection for parks

National parks need federal protection from "reckless" state governments, the Australian Greens say.

The minor party wants national parks, which currently fall under the jurisdiction of the states, to be covered by commonwealth law so any activities within them would require federal approval before going ahead.

"We need the federal government as a backstop against reckless state governments, mainly of the conservative persuasion, who are simply trashing the very little amount of land that's meant to be off-limits for logging, mining, grazing, shooting," Greens Senator Larissa Waters told reporters in Canberra on Wednesday.

"If we can't even protect the four per cent of Australia that is national parks, then something is going terribly wrong," she said.

The federal parks protection proposal follows concerns in NSW about hunting activity in the state's national parks.

As well, the Greens fear the Queensland government could allow a coal port expansion near the Great Barrier Reef to go ahead next year.

Greens Leader Christine Milne said if that happened the Great Barrier Reef could be put on a world heritage endangered list.